The total number of passengers who started journey at ABC airport from 9:00 AM to 11:00 PM can be modeled by the expression 90 x cubed plus 87 x squared plus 976 x plus 2560 and the number of flights took off at the airport from 9:00 AM to 11:00 PM was 15 x plus 32, where x is the number of hours since 9:00 AM. Which of the following expressions correctly describes the average number of passengers per flight?


a.
2 x squared plus 7 x plus 80


b.
3 x squared minus 5 x plus 80


c.
3 x squared plus 7 x plus 80


d.
6 x squared minus 7 x plus 80